M.B.
I had the same problem with my second son. You might try a sippy cup. However, I was never able to get my son to drink my breastmilk from a bottle or cup (even when I wasn't there). Some of these babies are very smart and very particular and really want the breastmilk straight from mama. One thing you might consider is bringing the baby and a babysitter with you to the conference. They can then bring the baby to you when they need to be fed or you can slip out of the conference for a brief time.
The good thing about this situation is that you are very close to being able to add solids, so the problem gets so much easier. I ended up reserving the solids for when the baby and I were separated and then breastfed all other times until he was 9 mos. old. Following this approach, he breastfed for a very long time. The good thing is that there never was an issue of weaning him from the bottle.
Good luck.